Deployable sleeves and related methods

ABSTRACT

A medical device may include a tubular sleeve configured for implantation in a body lumen, the sleeve having a first configuration with a first rigidity and a second configuration with a second rigidity greater than the first rigidity, the sleeve including: a flexible membrane defining an interior lumen; and a channel extending along the membrane.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This patent application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 15/806,620, filed on Nov. 8, 2017, which claims thebenefit under 35 U.S.C. § 119 to U.S. Provisional Patent Application No.62/419,707, filed on Nov. 9, 2016, the entireties of which areincorporated herein by reference.

TECHNICAL FIELD

Examples of the present disclosure relate generally to medical devicesfor deploying in a lumen of a patient and related methods fordeployment.

BACKGROUND

Medical devices that include sleeves may be deployed within a lumen of apatient for a variety of reasons. In some instances, sleeves aredeployed within the gastrointestinal system (e.g., the intestines) toreduce absorption of nutrients. Sleeves also may be deployed after abariatric procedure, such as a sleeve gastrectomy or a Roux-en-Y bypass,to protect a leak in a staple line or other damaged tissue area fromfood ingested by the patient. Sleeves have been used to treatgastroesophageal reflux disease (GERD) by implanting a stent within theesophagus with an attached sleeve extending into the patient's stomach.In other examples, sleeves are deployed in a patient's colon to protecta damaged area. In a variety of contexts, current sleeves may be made ofa material that lacks rigidity and support, making them difficult todeploy within the desired body lumen. For example, the sleeve materialmay kink or bunch during attempted deployment.

SUMMARY

Embodiments of the present disclosure relate to, among other things,medical devices for deploying in a lumen of a patient and relatedmethods for deployment. Each of the embodiments disclosed herein mayinclude one or more of the features described in connection with any ofthe other disclosed embodiments.

In one example, a medical device may include a tubular sleeve configuredfor implantation in a body lumen, the sleeve having a firstconfiguration with a first rigidity and a second configuration with asecond rigidity greater than the first rigidity, the sleeve including: aflexible membrane defining an interior lumen; and a channel extendingalong the membrane.

The medical devices described herein may additionally or alternativelyinclude one or more of the following features: the channel may beconfigured to receive and retain a fluid; the membrane may include apolymer; the medical device may further comprise an anchor coupled to aproximal end of the sleeve; the channel may include a self-sealingmaterial, a valve, or a cap at a proximal end; the channel may be one ofspiral-shaped or ring-shaped; the channel may include Nitinol; themedical device may further include an element secured to a distal end ofthe channel and extending through the channel to a proximal end of thechannel, wherein applying a proximal force to the element is configuredto at least one of axially shorten or radially shorten the sleeve, andreleasing the proximal force is configured to at least one of axiallylengthen or radially expand the sleeve; the channel may be defined by amaterial of the membrane; the channel may be radially outward of themembrane; the channel is not fluidly connected to the interior lumen;the channel may include perforations fluidly connecting the channel toan exterior of the sleeve; the channel may be configured to transformfrom the first configuration to the second configuration upon receipt ofa fluid in the channel; the medical device may further comprise a secondchannel extending along the membrane; or the channel may include aclosed distal end.

In another example, a medical device may include an anchor and a sleeveextending from the anchor, the sleeve including: a flexible membranedefining an interior lumen; and a channel configured to receive andretain a fluid.

The medical devices described herein may additionally or alternativelyinclude one or more of the following features: the channel may be one ofspiral-shaped or ring-shaped; the channel may be radially outward of themembrane; the channel is not fluidly connected to the interior lumen;the channel may include perforations fluidly connecting the channel toan exterior of the sleeve; or the channel may include a plurality ofrings and a plurality of segments connecting the plurality of rings.

In yet another example, a method for implanting a medical device in abody lumen of a patient may include inserting a sleeve into the bodylumen of the patient, the sleeve including a flexible membrane definingan interior lumen, and a channel; and injecting a fluid into thechannel, the channel retaining the fluid.

The method may additionally or alternatively include one or more of thefollowing features: injecting the fluid may include injecting the fluidthrough a self-sealing material or a valve at a proximal end of thechannel; injecting the fluid may at least one of cause a diameter of thesleeve to increase or cause a length of the sleeve to increase; themethod may further comprise using a vacuum source to remove at leastsome of the fluid from the channel; or injecting the fluid may cause arigidity of the channel to increase.

It may be understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the invention, as claimed. As used herein, theterms “comprises,” “comprising,” or any other variation thereof, areintended to cover a non-exclusive inclusion, such that a process,method, article, or apparatus that comprises a list of elements does notinclude only those elements, but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus. The term “exemplary” is used in the sense of “example,”rather than “ideal.”

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of thepresent disclosure and together with the description, serve to explainthe principles of the disclosure.

FIG. 1A illustrates a medical device that includes a sleeve according toan exemplary embodiment.

FIG. 1B illustrates a cross-sectional view of the sleeve of FIG. 1A,taken along line 1B-1B, according to an exemplary embodiment.

FIG. 1C illustrates a cross-sectional view of the sleeve of FIG. 1A,taken along line 1C-1C, according to an exemplary embodiment.

FIGS. 2A and 2B illustrate the ability of a sleeve to radially expand,according to an exemplary embodiment.

FIGS. 3A and 3B illustrate the ability of a sleeve to axially andradially expand, according to an exemplary embodiment.

DETAILED DESCRIPTION

The present disclosure is drawn to medical devices for deploying in alumen of a patient and related methods for deployment. In general, themedical devices may include a sleeve having a channel or other structurethat supports the sleeve during deployment and/or afterwards. Thechannel may have a modifiable rigidity to allow the sleeve to be lessrigid in a first state and more rigid in a second state. In someexamples, the channel may allow the sleeve to be radially expandedand/or contracted or axially expanded and/or contracted.

Referring to FIG. 1A, a medical device 2 may include a proximal anchor 4and a distal sleeve 6. Sleeve 6 may include a support 8 and a membrane10. In various examples, device 2 may have a length between 0.5-20 feet(0.15-6.1 meters), between 3-5 feet (0.9-1.5 meters), or about 2-4 feet(0.6-1.2 meters). However, the device may have a length of less than 0.5feet (0.15 meters) or greater than 20 feet (6.1 meters). Sleeve 6 may besecured to a distal end of anchor 4. In one example, as shown in FIG.1A, sleeve 6 extends partially into the lumen of anchor 4 and is securedby adhesive or other methods known in the art to anchor 4. In anotherexample, membrane 10 may extend substantially, or all, of a length ofdevice 2 and cover all other portions of device 2, including anchor 4.Membrane 10 may couple the sleeve 6 to the anchor 4.

Anchor 4 may be similar to a stent and may have a substantiallycylindrical shape. Portions of anchor 4 may have different diametersthan other portions. For example, a proximal portion of anchor 4 mayhave a larger diameter than a distal portion of anchor 4. In oneexample, anchor 4 may include a frame and a membrane covering the frame(e.g., a covered stent). In another example, anchor 4 may include a bareframe without a membrane (e.g., a bare stent). Anchor 4 may include alaser cut nitinol frame that resists elongation or does not elongate.Alternatively, anchor 4 may include a braided design. Anchor 4 may beself-expandable, like nitinol stents. In an alternative example, anchor4 may be expanded by an expansion device, such as a balloon insertedwithin a lumen of anchor 4. Anchor 4 may include a one-way valve, suchas an elastomeric slit valve or duck bill valve, to prevent retrogradeflow of gastro-intestinal fluids.

Once implanted in a patient, anchor 4 may exert a radially outward forceto help secure the device 2 to the body lumen. As described furtherbelow, anchor 4 may be positioned in the esophagus or thegastro-esophageal junction (GEJ) region, with sleeve 6 extending throughthe stomach or other portions of the gastro-intestinal system. Inanother example, anchor 4 may be positioned in the patient's intestine.In some examples, device 2 does not include anchor 4. Instead, sleeve 6may be secured directly to the patient's tissue using sutures or anyother suitable attachment mechanism.

Sleeve 6 may extend from the distal end of anchor 4 and may be have anelongated, tubular shape with an interior lumen. In one example,membrane 10 defines only one interior lumen. In an expandedconfiguration, sleeve 6 may be substantially cylindrical. Absent support8, membrane 10 may be a flexible, thin membrane that readily collapseson itself. However, at certain times, as will be described below,support 8 may provide rigidity and structure to sleeve 6.

Membrane 10 may include one or more of the following polymer materials:polyethylene, polypropylene, polystyrene, polyester, biosorbableplastics (e.g., polylactic acid), polycarbonate, polyvinyl chloride,polyacrylate, acrylate, polysulfone, polyetheretherketone, thermoplasticelastomers, thermoset elastomers (e.g,. silicone), poly-p-xylylene(parylene), flouropolymers (e.g., polytetrafluoroethylene (PTFE),polyvinylidene fluoride (PVDF), poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP)), bioplastics (e.g.,cellulose acetate). The sleeve may additionally or alternatively includeone or more of: polyurethane and its copolymers, ethylene vinyl-acetate,polyethylene terephthalate (PET), polyolefins, cellulosics, polyamides,acrylonitrile butadiene styrene copolymers, styrene isoprene butadiene(SIBS) block copolymers, acrylics, poly(glycolide-lactide) copolymer,Tecothane, PEBAX, poly(γ-caprolactone), poly(γ-hydroxybutyrate),polydioxanone, poly(γ-ethyl glutamate), polyiminocarbonates, poly(orthoester), and/or polyanhydrides. Blends of the above polymers may also beemployed.

Referring still to FIG. 1A, support 8 may form a spiral shape aroundmembrane 10. Support 8 may include a channel having an interior lumenwith an access point at a proximal end 12. The channel may have a closeddistal end 14, such that fluid inserted into the proximal end 12 doesnot exit the channel through distal end 14. The channel may be separatefrom the interior lumen of sleeve 6 and in one example is not fluidlyconnected to the interior lumen of sleeve 6. Proximal end 12 may includea self-sealing material or membrane to allow the channel to be accessedby a needle. The needle may be connected to a syringe or other pump toallow fluid (e.g., air, liquid, saline, contrast medium) to be injectedinto the channel. Contrast medium may be injected into the channel toaid in visualization of sleeve 6 using fluoroscopy or other imagingmethods. In another example, the proximal end 12 may include a valve orcap to allow access to the channel of support 8. After fluid has beeninjected into the channel, the channel may retain the fluid (e.g., via aself-sealing material, valve, or cap) until removal by a practitioner.

In one embodiment, support 8 extends around membrane 10 approximatelyfour times. However, the spiral shape may be tighter (e.g., support 8may extend around membrane 10 more than four times) or looser (e.g.,support 8 may extend around membrane 10 less than four times) than theexample shown in FIG. 1A. A tighter spiral may provide more support tosleeve 6, and a looser spiral may provide less support.

In various examples, support 8 may include different materials thatprovide different levels of rigidity. Support 8 may include a tubularchannel defined by a metal (e.g., Nitinol) or a polymer. In someexamples, the channel may be defined by the material of membrane 10(e.g., a polymer). If the channel is defined by the material of membrane10, it may have approximately the same rigidity as membrane 10.Accordingly, in an unfilled, first configuration, support 8 may bereadily collapsible along with membrane 10. However, when support 8 isfilled with fluid and expanded to a second configuration, support 8 mayincrease in rigidity to provide support to sleeve 6. The support 8, andtherefore sleeve 6, may have different rigidities at different axial orradial locations. Variations in rigidity may be achieved by varying thediameter of the channel, the pitch of the spiral, or the materialdefining the channel. For example, in locations where the channel has alarger diameter (see FIG. 1C), the sleeve may be more rigid when thechannel is filled than in locations where the channel has a smallerdiameter (see FIG. 1B). In another example, a spiral having a smallerpitch may cause corresponding segments of sleeve 6 to be more rigid,while a spiral having a larger pitch may cause corresponding segments ofsleeve 6 to be less rigid. In yet another example, a portion of thechannel may be defined by a material having a higher rigidity (e.g., ametal) and a portion may be defined by a material having a lowerrigidity (e.g., a flexible polymer).

Support 8 may extend along a perimeter of sleeve 6. Support 8 may bepositioned between two or more layers of material that form membrane 10(e.g., an interior layer and an exterior layer), or otherwise embeddedinto the material that forms membrane 10. In other examples, support 8may extend along the perimeter of sleeve 6 by being positioned proximateto membrane 10, either interior to membrane 10 or exterior to membrane10. FIGS. 1B-1C illustrate support 8 positioned exterior to membrane 10.If support 8 is positioned interior or exterior to membrane 10,appropriate adhesives or other bonding methods may be used to securesupport 8 to membrane 10, or support 8 and membrane 10 may be extrudedor otherwise formed as an integral one-piece construction.

The support 8 may include perforations that connect the channel ofsupport 8 to an exterior of sleeve 6. The perforations may allow drugsor other therapeutics to be delivered to the body lumen of the patient.The perforations may be evenly spaced along the length of sleeve 6 ormay be clustered in select locations to target certain body portions.Exemplary therapeutics deliverable through perforations in support 8include anti-inflammatories, antibiotics, antirestenosis (e.g.,Paclitaxel, everolimus), cytotoxins, stem cells, anti-coagulants, ordigestive enzyme aids.

In some examples, the sleeve 6 may include multiple supports 8. Eachsupport 8 may be spiral-shaped. The multiple supports may extendparallel to each other along the length of sleeve 6, or may extend inopposite directions such that the multiple spirals intersect with eachother at various points along the length of sleeve 6. Each support 8 mayserve the same or different purposes as the other supports 8. Forexample, one or more supports 8 may be configured to be filled with asubstance to provide the sleeve with additional rigidity, one or moresupports 8 may be used for drug delivery, and one or more supports 8 maybe filled with contrast medium.

Support 8 may include other configurations besides a spiral. Forexample, support 8 may include a plurality of rings around sleeve 6connected by a plurality of segments extending parallel to thelongitudinal axis of sleeve 6. If the support 8 includes channels, thevarious rings and segments of support 8 may be connected by a continuouslumen that allows inflation and deflation from a single proximal accesspoint.

FIGS. 2A and 2B illustrate the use of support 8 to radially expandsleeve 6. In FIG. 2A, support 8 is unfilled and in a firstconfiguration, and sleeve 6 has a first diameter D1 and a firstrigidity. Fluid F (e.g., air, liquid, saline, contrast medium) may beinjected into the proximal end 12 of support 8. The injected fluid maycause support 8 to increase in rigidity to a second rigidity greaterthan the first rigidity, which may cause the channel itself to expand(not shown) and/or may cause the sleeve 6 to radially expand. Theexpanded sleeve 6 is shown in FIG. 2B and has a diameter D2, in which D2is larger than D1. In some examples, sleeve 6 may also increase inlength when fluid is injected into support 8, as will be described inconnection with FIGS. 3A and 3B. In other examples, injecting fluid intosupport 8 may increase the rigidity of support 8 without causing sleeve6 to change in diameter or length. The rigidity of support 8 andaccordingly the radial and/or axial expansion of sleeve 6 may becontrolled by the amount of fluid that is injected into support 8.Injecting a small amount of fluid may cause a corresponding smallincrease in rigidity of support 8 and/or expansion of sleeve 6.Similarly, injecting a large amount of fluid may cause a correspondinglylarge increase in rigidity of support 8 and/or expansion of sleeve 6.After injection, the channel may retain the fluid until a practitionerdesires to remove the fluid from the channel, e.g., through aspirationapplied at proximal end 12.

FIGS. 3A and 3B illustrate the use of support 8 to both axially andradially constrict and expand sleeve 6. Support 8 may include a channelwith an elongated element, such as suture 14, extending through thechannel. The suture 14 may be secured to a distal end of the interior ofthe channel, e.g., via any suitable adhesive or method of securement. Toobtain the first, contracted configuration shown in FIG. 3A, a force maybe applied to suture 14 in a proximal direction to contract sleeve 6axially along its longitudinal axis to a length L1. The pulling ofsuture 14 may further cause support 8, and therefore sleeve 6, tocontract in a radial direction to a diameter D1. The support 8 mayinclude a shape memory material, such as Nitinol, along all or a portionof its length. Accordingly, when the suture 14 is released, the support8 may be biased to self-expand to the second, expanded configurationshown in FIG. 3B. In the second configuration, support 8 has causedsleeve 6 to expand both in an axial direction to length L2 and in aradial direction to diameter D2. In an alternative example to that shownin FIGS. 3A and 3B, the suture is eliminated and the support does notinclude a shape memory material. Instead, the channel of support 8 ofFIG. 3A may be filled with a fluid, as described in connection withFIGS. 2A and 2B, to cause the axial and radial expansion of sleeve 6shown in FIG. 3B.

Once implanted, the fluid may remain in the channel of support 8 toprovide continued support to sleeve 6. In another example, support 8 maybe inflated further to increase rigidity or deflated (e.g., by removingfluid) to allow sleeve 6 to revert to a less rigid, structuredconfiguration that places little to no force on adjacent tissue. Therigidity of support 8 may be decreased by applying a vacuum source tothe proximal end 12 of support 8. An intermediate fill level, achievedby either not inflating support 8 to a maximum amount or by removingsome fluid from a fully-inflated support 8, may provide some structuralsupport but still cause sleeve 6 to exert less outward force on adjacenttissue than a stent. Continued application of a vacuum to remove fluidfrom support 8 may cause sleeve 6 to contract in diameter and/or length,and/or to assume an unstructured, more floppy configuration. In otherexamples (e.g., if support 8 includes Nitinol or another rigidmaterial), support 8 may be restricted (e.g., by pulling suture 14)after the initial implantation to achieve a shortened length and/ordiameter of sleeve 6.

Support 8 may allow for size adjustment for patients having differentsized anatomies. For example, for patients having a smaller body lumen(e.g., intestine), support 8 may be filled only partially to expandsleeve 6. For patients with a larger body lumen, support 8 may be filledto a greater degree to cause sleeve 6 to expand to a wider diameter.Similarly, if support 8 includes a suture 14, the suture 14 may beadjusted to lengthen or shorten sleeve 6 or to increase or decrease itsdiameter. Post-implantation (e.g., days weeks, or months later), support8 may similarly allow for adjustments in the size of sleeve 6 to achievedifferent objectives. For example, for obesity treatment, sleeve 6 maybe lengthened or shortened to prevent or allow, respectively, certaindigestive juices from reacting with food or to reduce or increase,respectively, the absorption of food.

Sleeve 6 may be used in a variety of contexts. In one use, sleeve 6 maybe used to treat obesity. For example, sleeve 6 may be implanted intothe patient's intestines to reduce absorption of nutrients, with orwithout an anchor 4 to help secure sleeve 6. Anchor 4 may be positionednear or at the pylorus, with the sleeve 6 extending into the patient'sintestines. Alternatively, anchor 4 may be positioned in the patient'sGEJ region, with sleeve 6 extending though the stomach and into thepatient's intestines. The ability to modify the length of sleeve 6 maybe useful to adjust the level of nutrient absorption. For example,shortening sleeve 6 may allow the patient to absorb more nutrients,whereas lengthening sleeve 6 may further reduce nutrient absorption.

In another example, sleeve 6 may be implanted after a bariatricprocedure. Patients who undergo a sleeve gastrectomy or Roux-en-Yprocedure, for example, may develop leaks, infections, or othercomplications post-surgery. Anchor 4 may be positioned in an esophagusor in the GEJ region of the patient, and sleeve 6 may extend through astomach sleeve formed during the sleeve gastrectomy procedure or througha limb created during the Roux-en-Y procedure to protect the injuredarea. In yet another example, sleeve 6 may be used to protect thepatient's colon after colon surgery. Anchor 4 may be deployed proximalto the injured area, and sleeve 6 may extend over the injured tissue.

One currently-existing solution to protect injured portions of bodylumens is to position a covered stent within the lumen and over theinjured area, but stents may be traumatic to the weakened tissue.Placement of a sleeve, in contrast, may protect the injured area andallow food and other substances to bypass the injured area, withoutexerting unnecessary outward pressure on the injured tissue.Currently-existing sleeves, however, can be difficult to deploy and canwrinkle or bunch. In contrast, support 8 of sleeve 6 described hereinmay allow successful deployment by preventing sleeve 6 from wrinkling orbunching during deployment or afterwards, while exerting less outwardforce than a stent.

In another example, sleeve 6 may be used to treat gastro-esophagealreflux disease. Anchor 4 may be positioned in the patient's esophagus orthe GEJ region, and sleeve 6 may extend into the patient's stomach.Support 8 may be inflated during implantation to aid in correctpositioning of sleeve 6. After implantation, the fluid may be removedfrom support 8 so that the membrane 10 resumes a less rigid,unstructured configuration in which it can collapse onto itself. Themembrane prevents reflux of stomach contents by collapsing onto itselfbut allows food to flow through sleeve 6 in a proximal-to-distaldirection.

Sleeve 6 may be delivered to a patient using standard delivery methods.For example, sleeve 6 may be inserted into a delivery catheter andplaced transorally or transrectally into the patient's gastrointestinalsystem. As described herein, once inside the patient, fluid (e.g., air,liquid, saline, or contrast medium) may be inserted into a channel ofsupport 8 to increase the rigidity of support 8. In other embodiments, arestraint, such as a suture, may be released to allow support 8 toself-expand. The increased rigidity of support 8 and/or theself-expansion of support 8 may cause sleeve 6 to deploy moreeffectively that currently-existing sleeves. Sleeve 6 may be removedfrom the patient by removing any fluid from support 8 (if the fluid wasnot removed previously) and/or constricting support 8 using a suture orother method (e.g., physically constricting the sleeve within a tube).Sleeve 6 may then be pulled transorally or transrectally from thepatient.

While principles of the present disclosure are described herein withreference to illustrative embodiments for particular applications, itshould be understood that the disclosure is not limited thereto. Thosehaving ordinary skill in the art and access to the teachings providedherein will recognize additional modifications, applications,embodiments, and substitution of equivalents all fall within the scopeof the embodiments described herein. Accordingly, the invention is notto be considered as limited by the foregoing description.

1-20. (canceled)
 21. A medical device, comprising: a sleeve configuredto move from a first configuration to a second configuration, the sleeveincluding: a membrane having a length defined between a proximal end anda distal end; and a channel extending between the proximal end and thedistal end with a variable diameter such that a rigidity of the membranevaries along the length between the proximal end and the distal endbased on the variable diameter of the channel.
 22. The medical device ofclaim 21, wherein the channel includes a first portion having a firstdiameter and a second portion having a second diameter that is greaterthan the first diameter, such that the rigidity of the membrane along afirst segment of the membrane coinciding with the first portion of thechannel is less than the rigidity of the membrane along a second segmentof the membrane coinciding with the second portion.
 23. The medicaldevice of claim 21, wherein the channel extends along an exterior of themembrane in a spiral configuration between the proximal end and thedistal end of the membrane.
 24. The medical device of claim 21, whereinthe sleeve is configured to receive a fluid through the channel fordelivery to a body lumen positioned adjacent to the sleeve.
 25. Themedical device of claim 24, wherein the sleeve includes one or moreperforations fluidly connecting an interior lumen of the channel to anexterior of the membrane for delivering the fluid received in thechannel to the body lumen.
 26. The medical device of claim 21, whereinthe membrane has a first rigidity when in the first configuration, and asecond rigidity that is greater than the first rigidity when in thesecond configuration.
 27. The medical device of claim 21, wherein themembrane has a first length when in the first configuration, and asecond length that is greater than the first length when in the secondconfiguration.
 28. The medical device of claim 21, wherein the membranehas a first diameter when in the first configuration, and a seconddiameter that is greater than the first diameter when in the secondconfiguration.
 29. The medical device of claim 21, wherein the membraneincludes an anchor at the proximal end of the membrane that isconfigured to fix the sleeve to a body lumen, wherein the anchorincludes a frame that is covered by a second membrane.
 30. The medicaldevice of claim 21, wherein the sleeve is configured to move from thefirst configuration to the second configuration by: receiving a fluidthrough a proximalmost end of the channel that is open; and retainingthe fluid within the channel by a distalmost end of the channel that isclosed, thereby axially or radially expanding the membrane.
 31. Themedical device of claim 30, wherein the sleeve is configured to movefrom the second configuration to the first configuration by: releasingthe fluid from within the channel, thereby axially or radiallyshortening the membrane.
 32. The medical device of claim 21, wherein thesleeve is configured to move from the first configuration to the secondconfiguration by: receiving an element through a proximalmost end of thechannel that is open for attachment to a distalmost end of the channelthat is closed; and applying a force to the distalmost end of thechannel via the element, thereby axially or radially shortening themembrane.
 33. The medical device of claim 32, wherein the sleeve isconfigured to move from the second configuration to the firstconfiguration by: releasing the force applied to the distalmost end ofthe channel via the element, thereby axially or radially expanding themembrane.
 34. The medical device of claim 21, wherein the channel isformed of a shape-memory material that is configured to bias the sleeveto move from the first configuration to the second configuration. 35.The medical device of claim 21, wherein the membrane includes an outerlayer and an inner layer, and the channel is disposed between the outerlayer and the inner layer.
 36. The medical device of claim 21, whereinthe sleeve includes a second channel extending between the proximal endand the distal end of the membrane.
 37. A medical device, comprising: asleeve configured to move from a first configuration to a secondconfiguration, the sleeve including: a membrane having a length definedbetween a proximal end and a distal end; and a channel extending aroundan exterior of the membrane between the proximal end and the distal endwith a variable pitch such that a rigidity of the membrane varies alongthe length between the proximal end and the distal end based on thevariable pitch of the channel.
 38. The medical device of claim 37,wherein the channel includes a first portion having a first pitch and asecond portion having a second pitch that is greater than the firstpitch, such that the rigidity of the membrane along a first segment ofthe membrane coinciding with the first portion of the channel is lessthan the rigidity of the membrane along a second segment of the membranecoinciding with the second portion.
 39. A medical device, comprising: asleeve configured to move from a first configuration to a secondconfiguration, the sleeve including: a membrane having a length definedbetween a proximal end and a distal end; and a channel extending aroundan exterior of the membrane between the proximal end and the distal endwith a variable material composition such that a rigidity of themembrane varies along the length between the proximal end and the distalend based on the variable material composition of the channel.
 40. Themedical device of claim 39, wherein the channel includes a first portionhaving a first material composition and a second portion having a secondmaterial composition that is different than the first materialcomposition, such that the rigidity of the membrane along a firstsegment of the membrane coinciding with the first portion of the channelis different than the rigidity of the membrane along a second segment ofthe membrane coinciding with the second portion.